运行时每按一下键盘屏幕显示的字符应有变化,但是却没变化为啥??

DATAS SEGMENT
    dw 0,0;
DATAS ENDS

STACKS SEGMENT
STACKS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS,SS:STACKS
START:
    mov ax,0
    mov es,ax
    mov ax,datas
    mov ds,ax
    push es:[9*4]
    pop  ds:[0]
    push es:[9*4+2]
    pop  ds:[2]
   
    mov  word ptr es:[9*4],offset do1
    mov  es:[9*4+2],cs
   
    mov ah,2
    mov dl,3
   
lop:int 21h
   
    call delay
   
    jmp lop

    MOV AH,4CH
    INT 21H
   
delay: push ax
       push dx
      
       mov ax,0
       mov dx,1000h
  s:   sub ax,1
       sbb dx,0
       cmp ax,0
       jne s
       cmp dx,0
       jne s
       pop dx
       pop ax
       ret
               

do1: push ax
     push bx
     
     mov ax,datas
     mov ds,ax

     pushf
        
     pushf
     pop bx
     and bh,11111100b
     push bx
     popf
        
     call dword ptr ds:[0]
     
     inc dl
     
     pop bx
     pop ax
     iret
         
CODES ENDS
    END START

已经找到原因了,把delay子程序中的dx一律改成bx就行了